Types of Hermaphroditism and How It Occurs in Nature
An organism that produces both eggs and sperm is known as a hermaphrodite (cosexual). It can be sequential, in which case one sex is produced before the other, or simultaneously, in which case both eggs and sperm are produced at the same time (both sexes at the same time). An intersex or mixture of male and female genetics and/or phenotype organism is referred to as a hermaphrodite.
What is Hermaphrodite?
Hermaphrodites, the mythical Greek offspring of Hermes and Aphrodite, are from where the name "hermaphrodite" originates. Hermes is a symbol of strong, masculine identity. Aphrodite is a symbol of feminine beauty.
There are two sorts of hermaphrodites: true and false. A real hermaphrodite has a genetic deficiency (issues with the X or Y chromosome) in any combination of the following: XXX, XXY, X0, X+ Y. SYR loci are connected to the partial Y in true hermaphrodites with XX + part Y. (carries TDF which drives maleness). There are testicular and ovarian tissues in it (dysfunctional).
The chromosome structure of the fake hermaphrodite is usually XX or XY. It has a mutation in gene loci that code for enzymes involved in the manufacture of androgen or oestrogen (get less than normal levels). Because differentiating ducts/external genitalia are hormone-driven (have partials/incomplete characteristics), this causes issues.
Hermaphrodite Animals
The animals that have the characteristics to develop both male and female gametes in their body are known as hermaphrodite animals. These hermaphrodite animals have some features and organs that help to adapt to this condition.
Worms, bryozoans (moss creatures), trematodes (flukes), snails, slugs, and barnacles are examples of hermaphrodite animals examples. Hermaphrodites include animals mostly in the phylum Platyhelminthes, including liver fluke and blood fluke. All leeches are hermaphrodites, meaning they can be either protandrous or cosexual. Most sponges are hermaphrodites who go through phases of being one sex and then the other. Earthworms, flatworms, mollusks, and fish(rarely) are all examples of each member who can act as both a man and a woman.
A free martin is a fake hermaphrodite found only in cattle. When twins are born, one male and one female, and the placentas fuse together (can occur early or late).
Snails
Hermaphrodites make up the majority of snails. Apple snails and periwinkle snails are the only freshwaters and marine species that are exempt.
Snails, in addition to being hermaphroditic, are also early bloomers, reaching sexual maturity by the age of a year.
The Achatina fulica, or gigantic African land snail, is the world's largest snail species, capable of depositing up to 500 eggs at a time. They mate with partners most of the time as hermaphrodites, although they can also self-fertilise in rare cases.
Image: A Hermaphrodite animal- Snail
Worms
Worms are another class of invertebrates that contribute to the spread of hermaphroditism.
Some worms can fertilise themselves, but most worms require a mate in order to breed.
Consider the mating behaviour of an earthworm. Earthworms connect together with their heads facing opposite ways during fertilisation and transmit sperm and eggs between them into a united cocoon.
When an earthworm emits a pheromone that signals it's ready to reproduce, it can happen above or below the soil. Caenorhabditis elegans is a free-living organism and both sex in a single body.
Frogs
Some frog species, such as the African tree frog (Xenopus laevis), are male in their juvenile stages before becoming female as adults.
Frogs' sex is fast changing due to commercial pesticides based on atrazine.
Banana Slugs
This mollusc tends to pair with a partner, but if one isn't available, it can self-fertilise.
For how they mate, being a hermaphrodite is a crucial trait of the banana slug. Banana slugs become caught together during the mating process, and because their male reproductive organs are so enormous, the organ is chewed off to separate the organs.
This causes no harm to the slug, and it can still mate with other slugs because it still has its female reproductive apparatus.
Fishes
Hamlet is a fish that does not reproduce like other fishes. It changes its sex after finding its mate.
If a mate is male then it changes itself to female and if a mate is female then changes to male and reproduces.
Starfish
The jellyfish are among the most well-known hermaphroditic animals on the planet.
They generally produce a male reproduction organ in their immature stages and then transition to a female reproductive organ as they mature.
Conclusion
The hermaphrodites are a type of sexual reproduction. It carries both genders and helps in self-fertilisation. Hermaphrodites that may mate with males or self-fertilise. This condition occurs in both plants and animals. They have no genetic variation. Slugs, worms, and plants exhibit hermaphroditic traits more frequently and pronouncedly than do people.
The above article provides all the information about examples of them in which this process occurs. The examples are helpful to identify the organism that has this type of characteristics.
FAQs on Hermaphrodite in Biology: Meaning and Examples
1. What is the definition of a hermaphrodite in biology?
In biology, a hermaphrodite is an organism that possesses both male and female reproductive organs. This means a single individual can produce both male gametes (sperm) and female gametes (eggs). This condition is common in many plants and invertebrate animals.
2. What are some common examples of hermaphrodite animals?
Hermaphroditism is found in various animal groups, particularly among invertebrates. Common examples include:
- Earthworms: They have both male and female organs but typically cross-fertilise with another worm.
- Snails and Slugs: Most land and freshwater snails are simultaneous hermaphrodites.
- Tapeworms and Flukes: Many parasitic flatworms are hermaphroditic, which is an adaptation to their parasitic lifestyle.
- Barnacles: These sessile marine crustaceans are also hermaphrodites.
- Some species of fish: Certain fish, like the clownfish, are sequential hermaphrodites, meaning they can change their sex during their lifetime.
3. What is the difference between a simultaneous and a sequential hermaphrodite?
The key difference lies in the timing of the presence of male and female functions. A simultaneous hermaphrodite, like an earthworm, possesses both male and female reproductive organs at the same time throughout its adult life. In contrast, a sequential hermaphrodite changes its sex at some point in its life. For example, a clownfish is born male and can later become a female.
4. Are there hermaphroditic plants, and what are they called?
Yes, hermaphroditism is extremely common in the plant kingdom. Most flowering plants (angiosperms) are hermaphrodites. A plant with flowers that contain both male parts (stamens) and female parts (pistil or carpel) is considered hermaphroditic. These are often referred to as having bisexual or perfect flowers. This setup greatly facilitates pollination and self-pollination.
5. Are humans considered true hermaphrodites in a biological sense?
No, humans are not true hermaphrodites. While the term was historically used, it is now considered outdated and inaccurate for humans. A true hermaphrodite possesses fully functional male and female gonads. In humans, conditions where there are variations in sex characteristics (chromosomes, gonads, or genitals) are correctly referred to as intersex. An intersex person does not have two fully functional sets of reproductive organs.
6. What is the primary evolutionary advantage of hermaphroditism?
The main evolutionary advantage is reproductive assurance. When an organism is hermaphroditic, any other individual of the same species is a potential mate. This doubles the chances of reproductive success, which is especially beneficial for species that are slow-moving (like snails), live in low-density populations, or are sessile (like barnacles), as it reduces the energy and risk associated with finding a specific mate of the opposite sex.
7. If hermaphroditism is advantageous, why isn't it more common in complex vertebrates like mammals?
Hermaphroditism is rare in complex vertebrates due to several factors. Firstly, maintaining two distinct and fully functional reproductive systems is energetically very expensive. Secondly, separate sexes (gonochorism) promote outcrossing and genetic diversity, which is a powerful defence against parasites and changing environments. Hermaphroditism carries a higher risk of inbreeding depression if self-fertilisation occurs, which can reduce the fitness of offspring.
8. How do most hermaphroditic animals like earthworms avoid self-fertilisation?
Even though they have both sets of organs, many hermaphrodites have mechanisms to prevent self-fertilisation and promote genetic diversity. Earthworms, for example, engage in cross-fertilisation. Two worms align themselves and exchange sperm, which is then stored in a receptacle. The eggs are fertilised later by the stored sperm from the other worm, not by the worm's own sperm. This ensures a mixing of genes.
9. How does reproduction in a hermaphrodite compare to reproduction in a species with separate sexes?
The main comparison is mate selection and energy investment. In species with separate sexes (gonochoristic), reproduction requires finding a compatible partner of the opposite sex, often involving complex courtship and competition. In hermaphrodites, the pool of potential mates includes every individual. While some can self-fertilise, most cross-fertilise, but the search for a mate is simplified. The energy cost is shifted from mate searching and competition to maintaining dual reproductive systems.
10. What is the key biological distinction between a hermaphrodite and an intersex individual?
The distinction is primarily about biological functionality and the species in question. A hermaphrodite is an organism (typically a plant or invertebrate) with two fully functional sets of reproductive organs, capable of producing both sperm and eggs. The term intersex is used for humans born with a range of variations in sex characteristics that do not fit the typical binary definitions of male or female. These variations can be in chromosomes, gonads, hormones, or genitalia, and do not result in two separate, fully functional reproductive systems.
